Method for Producing a Housing of a Rotary Screw Compressor

ABSTRACT

A method produces a housing of a rotary screw compressor, the housing having at least one housing body and at least one housing cover. The method includes the following steps: bearing seats for at least one screw rotor of the rotary screw compressor are provided in the housing body and in the housing cover; at least one screw borehole for the at least one screw rotor of the rotary screw compressor is provided in the housing body; the housing body and the housing cover are temporarily assembled using at least one alignment tool for ensuring the alignment of the screw rotor central axis with the central axes of the bearing seats and the screw borehole; and at least one bolt insertion opening is provided in both the housing body and the housing cover by at least one common production process.

BACKGROUND AND SUMMARY OF THE INVENTION

The present invention relates to a method for producing a housing of a screw compressor, wherein the housing has at least one housing body and at least one housing cover.

The present invention furthermore relates to a housing of a screw compressor and to a screw compressor.

Such methods for producing housings of screw compressors, and correspondingly produced housings of screw compressors, are already known from the prior art.

DD 2003 49 A1 presents a device for forming end walls on screw-type machines having at least two screw rotors, which are arranged parallel and which engage into one another in pairwise fashion, a working chamber which is composed of a casing wall tightly surrounding the screw rotors, and the end walls.

DE 37 37 358 A1 discloses a rotor housing for an internally mounted screw spindle pump, and a corresponding production method. Here, receiving bores of the screw spindle are provided in a housing body. For this purpose, disk-like material pieces which have the receiving bores of the screw spindle and which are composed of wear-resistant material are inserted into the housing. The wear-resistant material may in particular be ceramic, and may be arranged axially one behind the other in accordance with the lining length. The invention furthermore comprises a method for producing said housing, according to which the wear-resistant material pieces are cast into the housing body by means of plastic.

DE 40 16 841 A1 has disclosed a method for producing a rotor housing of a screw spindle pump. In order to avoid the production-induced difficulties that arise in the case of the previous production method by means of drilling and reaming of overlapping bores, the housing is centrally split, such that a change can be made from internal machining to external machining by means of profile milling or profile grinding.

DE 19 48 589 A1 presents a method for producing housings for screw pumps. Here, the production method has multiple steps, wherein the housing is produced in unmachined form with bores larger than the finished dimension, and in each case one relatively small mandrel or core is inserted into each bore. Subsequently, a curing plastic is introduced into the annular space between mandrel and bore wall, and the mandrel is pulled out after the plastic has cured.

The screw rotors of a screw compressor are fastened or mounted at both ends by means of rolling bearings in the housing. It is basically necessary for the housing to be formed in two parts owing to manufacturing and assembly requirements.

In order to realize the centering of the corresponding bearing seats of the screw rotors, the use of fit bolts or centering pins is generally proposed for this purpose.

Furthermore, the housing body and cover are machined in different manufacturing steps, such that manufacturing accuracy and coaxiality cannot be easily realized.

It is therefore the object of the present invention to advantageously further develop a method for producing a housing of a screw compressor of the type mentioned in the introduction, in particular such that the manufacturing process is simplified overall, and at the same time the manufacturing accuracy can be increased.

This object is achieved according to the invention by a method for producing a housing of a screw compressor, which method produces a housing of a screw compressor, wherein the housing has at least one housing body and at least one housing cover. The method includes the steps of:

-   -   forming bearing seats for at least one screw rotor of the screw         compressor in the housing body and in the housing cover;     -   forming at least one screw bore for the at least one screw rotor         of the screw compressor in the housing body;     -   provisionally assembling the housing body and housing cover         using at least one alignment tool in order to ensure the         alignment of the screw rotor central axis with the central axes         of the bearing seats and of the screw bore; and     -   forming at least one bolt insertion opening into both housing         body and housing cover by way of at least one joint         manufacturing process.

The invention is based on the underlying concept of the bolt insertion openings being formed such that they are manufactured already with the correct alignment of the bearing seats and of the screw bores with the aid of an alignment tool in the housing of the screw compressor. It is furthermore the underlying idea that, on the basis of the provisionally assembled housing body and housing cover which are already correctly aligned with respect to one another by means of the alignment tool, the bolt insertion opening is then formed both in the housing body and in the housing cover by means of a single manufacturing process, such that the bolt insertion opening is already correctly oriented. In this way, greater accuracy is achieved than would be possible in the case of separate manufacture of the bolt insertion openings in the housing body and housing cover respectively, such that, furthermore, greater accuracy of the outer diameter of the screw rotor which is provided within the screw bore in the housing body can be realized. Furthermore, as a result of the joint manufacturing process of the bolt insertion openings, the position tolerance of mutually aligned bolt insertion opening pairs in the housing body and housing cover (for example in relation to the bearing seats) can be chosen to be less exact, which yields an additional simplification of the production process.

Furthermore, provision may be made whereby the formation of the bearing seats for the at least one screw rotor of the screw compressor in the housing body and in the housing cover is performed in separate manufacturing processes. Firstly, by means of the separate formation of the bearing seats in housing cover and housing body, the design possibilities with regard to the respective arrangement of the bearing seats therein is increased, and secondly, the manufacture thereof is simplified. Accordingly, the outlay in terms of manufacturing for the joint formation of the bearing seats would be considerably greater, because for example the joint clamping and alignment of housing cover and housing body, and/or the manufacturing tool, would be made much more complicated.

Furthermore, provision may be made whereby, in conjunction with the provisional assembly of housing body and housing cover, the housing body and housing cover are fastened to one another by means of at least one screw connection. In this way, slippage or a relative movement between housing body and housing cover is prevented. The centering or alignment is ensured by means of the alignment tool.

It is also conceivable that, in conjunction with the provisional assembly of housing body and housing cover, the alignment tool is pushed in from outside through the bearing seat for the screw rotor in the housing cover and through the screw bore and is thus inserted into the bearing seats in the housing body and in the housing cover. Great variability in the mutual alignment of housing cover and housing body is achieved in this way, because the alignment tool can, by means of a very simple installation process, even in the case of an already loosely pre-mounted housing cover, be pushed in through said housing cover into the housing body and inserted into the corresponding bearing seat therein. It is however also possible for the alignment tool and the housing cover to firstly be jointly preassembled and only subsequently joined together and aligned with the housing body.

Provision may furthermore be made whereby the screw connection is tightened only after the insertion of the alignment tool into the bearing seats in the housing body and in the housing cover, such that, during the pushing-in and insertion of the alignment tool, the bearing seats in the housing cover and in the housing body can be aligned relative to one another. For error-free alignment of the bearing seats in housing body and housing cover, it is imperatively necessary for the screw connection to be tightened only when the two components are already in an aligned state. If the tightening of the screw connection were performed before the housing body and housing cover have actually been aligned, undesired stresses would arise between housing cover, alignment tool and housing body, which should be avoided in any case. Furthermore, under these circumstances, the normally very expensive alignment tool may be damaged and thus rendered unusable for further use.

It is additionally conceivable for the alignment tool to be of cylindrical and stepped form such that it has at least one first bearing insertion portion with a first diameter and at least one second bearing insertion portion with a second diameter. Normally, the screw rotors are mounted by means of circular rolling bearings, imperatively giving rise to the cylindrical design of the bearing seats within the housing body and the housing cover. In order to ensure an optimum alignment of these components, the shape of the alignment tool should therefore likewise be of cylindrical form, resulting in optimum fit accuracy with the respective bearing seats. Owing to the stepped formation of the alignment tool and the resulting first and second diameters, the installation thereof can be simplified, because it can firstly, by means of the first, relatively small diameter, be pushed in through the bearing seat of the housing cover into the housing body and correspondingly inserted. Furthermore, by means of the stepped formation, an axial stop is formed, whereby axially defined positioning of the first bearing insertion portion and of the second bearing insertion portion in the bearing seats is ensured.

It is furthermore conceivable that, after the insertion of the alignment tool, the first bearing insertion portion thereof is inserted in the bearing seat in the housing body and the second bearing insertion portion is inserted in the bearing seat in the housing cover. By means of the insertion of the first bearing insertion portion in the bearing seat within the housing body and the insertion of the second bearing insertion portion in the bearing seat within the housing cover, the alignment of said bearing seats can be realized with high accuracy. In order to additionally increase the alignment accuracy, the shape and/or position tolerances of the first and second bearing insertion portions may be configured to be more exact than the rest of the shape structures of the alignment tool. A further advantage is that only certain portions, specifically the first and second bearing insertion portion of the alignment tool, need to be machined, such that the production costs of the alignment tool can be reduced.

It is likewise conceivable that, after the provisional assembly, the manufacturing direction during the joint manufacturing process of the at least one bolt insertion opening runs from an outer side of the housing cover axially inwardly in the direction of the open end, facing toward the housing cover, of the housing body. This configuration of the joint manufacturing process of the at least one bolt insertion opening permits very easy access, during the production thereof, from an outer side of the housing cover, whereby complex manufacturing steps, which under some circumstances are difficult to control, can be omitted, and the production process is additionally shortened.

Provision may furthermore be made whereby the joint manufacturing process of the at least one bolt insertion opening is performed by means of at least one cutting manufacturing process, in particular by means of drilling. The use of a cutting manufacturing process for the formation of the at least one bolt insertion opening is particularly advantageously expedient here owing to its widely proven application and the good levels of manufacturing accuracy that can be attained within reasonable times. Since the chip volume associated with the formation of the bolt insertion opening is relatively small, a drilling process is particularly expedient in this regard. Other manufacturing processes that are suitable in this context, such as milling, erosion, reaming or grinding or combinations of these, may likewise be used.

It is furthermore conceivable that the cutting manufacturing process is performed by means of at least one cutting manufacturing tool, in particular a drilling tool, wherein the manufacturing tool is rotated and is of rotationally symmetrical form. In order to lower tool costs, tool variety and assembly and clamping costs, it is particularly advantageous for the cutting manufacturing process to be performed only by means of one cutting manufacturing tool, in particular one drilling tool. The drilling tool may in this case be formed as a spiral drill, as a drilling rod, as a reamer or in some other suitable manner. The drilling tool may furthermore be formed from steel, in particular HSS steel, hard metal, from steel with a hard metal coating, from steel with integrated hard metal cutting plates, or from some other suitable materials or material combinations.

After the provisional assembly, housing body and housing cover may be separated from one another for at least one further machining or assembly step. These may for example be further machining steps such as milling of further working surfaces, cleaning, deburring and/or for example the insertion of the components provided in the housing interior, or the like.

Furthermore, provision may be made whereby, during the assembly of housing body and housing cover, a fit bolt is inserted into the at least one bolt insertion opening, which fit bolt is seated both partially in the housing body and partially in the housing cover. By means of the fit bolt, it is possible in the assembled state for the alignment of housing body and housing cover relative to one another to be ensured. An additional fastening of housing cover to housing body may be realized by additional fastening means, such as screws.

Provision may furthermore be made for at least two bolt insertion openings to be provided both in the housing cover and in the housing body. Through the use of two bolt insertion openings both in the housing cover and in the housing body, the accuracy of the alignment of housing cover relative to housing body can be improved. The use of more than two bolt insertion openings in the housing body and housing cover may however lead to overdeterminacy and a more difficult assembly process, such that the use of in each case two bolt insertion openings is therefore particularly advantageous.

The present invention furthermore relates to a housing of a screw compressor obtained by means of the method described above.

The present invention furthermore relates to a screw compressor having a housing obtained by means of the method described above.

Further details and advantages of the invention will now be discussed in more detail on the basis of an exemplary embodiment illustrated in the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic sectional illustration of an exemplary embodiment of a screw compressor according to the invention, the housing of which has been produced by means of a production method according to the invention;

FIG. 2 shows a sectional illustration through the housing, produced by means of the production method according to the invention, of the screw compressor as per FIG. 1, as the bolt insertion openings are being formed;

FIG. 3 shows a sectional illustration through the housing, produced by means of the production method according to the invention, of the screw compressor as per FIG. 1, after the bolt insertion openings have been formed;

FIG. 4 shows a sectional illustration through the housing, produced by means of the production method according to the invention, of the screw compressor as per FIG. 1, after assembly of the housing.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 shows, in a schematic sectional illustration, a screw compressor 10 in the context of an exemplary embodiment of the present invention, the housing 20 of which screw compressor is produced by means of a production method according to the invention.

The screw compressor 10 has a fastening flange 12 for the mechanical fastening of the screw compressor 10 to a drive (not shown in any more detail here) in the form of an electric motor.

What is shown, however, is the input shaft 14, by which the torque from the electric motor is transmitted to one of the two screw rotors 16 and 18, specifically the screw rotor 16.

The screw rotor 18 meshes with the screw motor 16 and is driven by means of the latter.

The screw compressor 10 has a housing 20 in which the main components of the screw compressor 10 are accommodated.

The housing 20 is filled with oil 22.

At the air inlet side, an inlet connector 24 is provided on the housing 20 of the screw compressor 10.

The inlet connector 24 is in this case designed such that an air filter 26 is arranged at said inlet connector.

Furthermore, an air inlet 28 is provided radially on the air inlet connector 24.

In the region between the inlet connector 24 and the point at which the inlet connector 24 joins to the housing 20, there is provided a spring-loaded valve insert 30, which is designed here as an axial seal.

This valve insert 30 serves as a check valve.

Downstream of the valve insert 30, there is provided an air feed channel 32 which feeds the air to the two screw rotors 16, 18.

At the outlet side of the two screw rotors 16, 18, there is provided an air outlet pipe 34 with a riser line 36.

In the region of the end of the riser line 36, there is provided a temperature sensor 38 by means of which the oil temperature can be monitored.

Also provided in the air outlet region is a holder 40 for an air deoiling element 42.

In the assembled state, the holder 40 for the air deoiling element has the air deoiling element 42 in the region facing toward the base (as also shown in FIG. 1).

Also provided, in the interior of the air deoiling element 42, is a corresponding filter screen or known filter and oil separating devices 44, which will not be specified in any more detail.

In the central upper region in relation to the assembled and operationally ready state (that is to say as shown in FIG. 1), the holder for the air deoiling element 42 has an air outlet opening 46 which leads to a check valve 48 and a minimum pressure valve 50.

The check valve 48 and the minimum pressure valve 50 may also be formed in one common combined valve.

The air outlet 51 is provided downstream of the check valve 48.

The air outlet 51 is generally connected to correspondingly known compressed-air consumers.

In order for the oil 22 that is situated and separated off in the air deoiling element 42 to be returned into the housing 20, a riser line 52 is provided which has a filter and check valve 54 at the outlet of the holder 40 for the air deoiling element 42 at the transition into the housing 20.

A nozzle 56 is provided, downstream of the filter and check valve 54, in a housing bore.

The oil return line 58 leads back into approximately the central region of the screw rotor 16 or of the screw rotor 18 in order to feed oil 22 thereto again.

An oil drain screw 59 is provided within the base region, in the assembled state, of the housing 20.

By means of the oil drain screw 59, a corresponding oil outflow opening can be opened, via which the oil 22 can be drained.

Also provided in the lower region of the housing 20 is the attachment piece 60 to which the oil filter 62 is fastened. Via an oil filter inlet channel 64, which is arranged in the housing 20, the oil 22 is conducted firstly to a thermostat valve 66.

Instead of the thermostat valve 66, it is also possible for an open-loop and/or closed-loop control device to be provided by means of which the oil temperature of the oil 22 situated in the housing 20 can be monitored and set to a setpoint value.

Downstream of the thermostat valve 66, there is then the oil inlet of the oil filter 62, which, via a central return line 68, conducts the oil 22 back to the screw rotor 18 or to the screw rotor 16 again, and also to the oil-lubricated bearing 70 of the shaft 14.

Also provided in the region of the bearing 70 is a nozzle 72, which is provided in the housing 20 in conjunction with the return line 68.

The cooler 74 is connected to the attachment piece 60.

In the upper region of the housing 20 (in relation to the assembled state), there is situated a safety valve 76, by means of which an excessively high pressure in the housing 20 can be dissipated.

Upstream of the minimum pressure valve 50, there is situated a bypass line 78, which leads to a relief valve 80.

Via said relief valve 80, which is activated by means of a connection to the air feed 32, air can be returned into the region of the air inlet 28.

In this region, there may be provided a ventilation valve (not shown in any more detail) and also a nozzle (diameter constriction of the feeding line).

Furthermore, approximately at the level of the line 34, an oil level sensor 82 may be provided in the outer wall of the housing 20.

Said oil level sensor 82 may for example be an optical sensor, and may be designed and configured such that, on the basis of the sensor signal, it can be identified whether the oil level during operation is above the oil level sensor 82 or whether the oil level sensor 82 is exposed, and thus the oil level has correspondingly fallen.

In conjunction with this monitoring, it is also possible for an alarm unit to be provided which outputs or transmits a corresponding error message or fault message to the user of the system.

The function of the screw compressor 10 shown in FIG. 1 is as follows.

Air is fed via the air inlet 28 and passes via the check valve 30 to the screw rotors 16, 18, where the air is compressed.

The compressed air-oil mixture, which, having been compressed by a factor of between 5 and 16 downstream of the screw rotors 16 and 18, rises through the outlet line 34 via the riser pipe 36, is blown directly onto the temperature sensor 38.

The air, which still partially carries oil particles, is then conducted via the holder 40 into the air deoiling element 42 and, if the corresponding minimum pressure is attained, passes into the air outlet line 51.

The oil 22 situated in the housing 20 is kept at operating temperature via the oil filter 62 and possibly via the heat exchanger 74.

If no cooling is necessary, the heat exchanger 74 is not used and is also not activated.

The corresponding activation is performed by means of the thermostat valve 66. After purification in the oil filter 62, oil is fed via the line 68 of the screw rotor 18 or of the screw rotor 16, and also to the bearing 70.

The screw rotor 16 or the screw rotor 18 is supplied with oil 22 via the return line 52, 58, and the purification of the oil 22 takes place here in the air deoiling element 42.

By means of the electric motor (not shown in any more detail), which transmits its torque via the shaft 14 to the screw rotor 16, which in turn meshes with the screw rotor 18, the screw rotors 16 and 18 of the screw compressor 10 are driven.

By means of the relief valve 80 (not shown in any more detail), it is ensured that the high pressure that prevails for example at the outlet side of the screw rotors 16, 18 in the operational state cannot be enclosed in the region of the feed line 32, and that, instead, in particular during the start-up of the compressor, there is always a low inlet pressure, in particular atmospheric pressure, prevailing in the region of the feed line 32.

Otherwise, upon a start-up of the compressor, a very high pressure would initially be generated at the outlet side of the screw rotors 16 and 18, which would overload the drive motor.

FIG. 2 shows a sectional illustration through the screw compressor 10 as per FIG. 1, the housing 20 according to the invention of which is manufactured by means of a production method according to the invention.

FIG. 2 also shows the joint manufacturing process during the formation of the bolt insertion openings 104.

The housing 20 is composed of a housing body 20 a and a housing cover 20 b.

The housing body 20 a is of substantially pot-shaped form and has an open end 120 and an oppositely situated partially open end 124.

Furthermore, the housing body 20 a is an integral constituent part of the housing 20 of the screw compressor 10.

In the interior of the housing body 20 a, there are furthermore formed two screw bores 112, 114 for the two screw rotors 16, 18.

Two bearing seats 108 are formed within the partially open end 124 of the housing body 20 a.

The two bearing seats 108 are formed substantially as cylindrical passage bores in the partially open end 124 of the housing body 20 a.

One of the two bearing seats 108 is formed as a stepped passage bore with a first, relatively large diameter as first bearing seat portion.

The further portion of the passage bore with the relatively small diameter is formed as a first cylindrical transition bore and extends from the first bearing seat portion to an outer surface of the partially open end 124 of the housing body 20 a.

The other screw bearing seat 108 is formed as a non-stepped passage bore with a substantially continuously uniform diameter dimension.

The non-stepped passage bore is divided axially into a second bearing seat portion and a second cylindrical transition bore.

The second cylindrical transition bore extends from the second bearing seat portion to an outer surface of the partially open end 124 of the housing body 20 a.

The open end 120 of the housing body 20 a has a planar surface 126 which is oriented perpendicular to the central axes of the two bearing seats 108.

On the planar surface 126 of the housing body 20 a, the housing cover 20 b is arranged by way of a further planar inner surface 128.

The housing body 20 a and the housing cover 20 b have multiple screw connections (not illustrated in FIG. 2).

The two screw bores 112, 114 are, in the assembled state of the housing 20, spatially delimited not only by the pot-like structure of the housing body 20 a but also by the planar inner surface 128 of the housing cover 20 b.

The planar inner surface 128 of the housing cover 20 b is likewise oriented substantially perpendicular to the central axes of the bearing seats 108.

Two further bearing seats 110 are formed within the housing cover 20 b.

The two further bearing seats 110 are formed substantially as cylindrical countersunk bores within a planar outer surface 130 of the housing cover 20 b.

The bearing seats 110 are furthermore connected in each case by means of a cylindrical transition bore within the housing cover 20 b to the screw bores 112, 114, which transition bore is arranged in each case between the bearing seats 110 and the screw bores 112, 114.

The bearing seats 110 of the housing cover 20 b and the two bearing seats 108 of the housing body 108 are, in the assembled state of the housing 20, aligned substantially coaxially with respect to one another.

In FIG. 2, in the provisionally assembled state of the housing 20, two alignment tools 100, 102 have been inserted into the bearing seats 108 of the housing body 20 a and into the bearing seats 110 of the housing cover 20 b.

The alignment tools 100, 102 are in each case of cylindrical and stepped form.

The alignment tools 100, 102 are consequently composed in each case of a first elongate cylinder and a second cylinder, which is connected integrally and coaxially by means of an end side to an end side of the first elongate cylinder.

The diameter of the second cylinder is furthermore larger than the diameter of the first elongate cylinder.

The alignment tools 100, 102 have an axial stop at the transition in each case between the first elongate cylinder and second cylinder.

The alignment tools 100, 102 furthermore each have a first bearing insertion portion 116 with a first diameter.

Furthermore, the alignment tools 100, 102 each have a second bearing insertion portion 118 with a second diameter.

The first bearing insertion portion 116 is arranged at the free end portion of the first elongate cylinder.

The second bearing insertion portion 118 in turn is arranged at that end portion of the second cylinder which faces toward the first elongate cylinder.

The two alignment tools 100, 102 extend continuously from the bearing seats 110 of the housing cover 20 b through the screw bores 112, 114 to the bearing seats 108.

The first bearing insertion portion 116 is consequently inserted in each case in the bearing seat 108 in the housing body 20 a, and the second bearing insertion portion 116 is inserted in each case in the bearing seat 110 in the housing cover 20 b.

Two bolt insertion openings 104 are provided in the housing body 20 a.

The two bolt insertion openings 104 are formed as countersunk bores or blind bores in an outer circumferential region of the planar surface 126 of the open end 120 of the housing body 20 a by means of a drilling tool 122.

In the housing cover 20 a, there are likewise provided two bolt insertion openings 104, which are formed as passage bores.

The two bolt insertion openings 104 are formed as passage bores in an outer circumferential region of the planar inner surface 128 of the housing cover by means of a drilling tool 122.

The two bolt insertion openings 104 of the housing body 20 a and of the housing cover 20 b may be aligned at an alignment angle of 180° with respect to one another.

Other suitable alignment angles or alignment spacings of the bolt insertion openings 104 of the housing body 20 a and of the housing cover 20 b with respect to one another are likewise conceivable.

FIG. 3 shows a sectional illustration through the housing 20, produced by means of the production method according to the invention, as per FIG. 2, after the bolt insertion openings 104 have been formed.

In FIG. 3, in the provisionally assembled state of the housing 20, the two bolt insertion openings 104, formed both in the housing body 20 a and in the housing cover 20 b, are aligned so as to be coaxially flush with one another.

FIG. 4 shows a sectional illustration through the housing 20, produced by means of the production method according to the invention, as per FIG. 2, after assembly of the housing 20.

In FIG. 4, in the assembled state of the housing 20, one fit bolt 106 has been inserted into each of the two bolt insertion openings 104 both of the housing body 20 a and of the housing cover 20 b.

The two fit bolts 106 are inserted both partially in the housing body 20 a and partially in the housing cover 20 b.

Furthermore, in the assembled state of the housing 20, all of the components required for the operation of the screw compressor 10, such as for example the screw rotors 16, 18, are arranged within the housing 20.

For the production of the housing 20 of the screw compressor 10, the following procedure is followed here.

Firstly, bearing seats 108, 110 for the screw rotors 16, 18 of the screw compressor 10 are formed in the housing body 20 a and in the housing cover 20 b.

The formation of the bearing seats 108, 110 for the two screw rotors 16, 18 of the screw compressor 10 in the housing body 20 a and in the housing cover 20 b is however performed in separate manufacturing processes.

The formation of the cylindrical transition bores of the bearing seats 108, 110 into housing body 20 a and housing cover 20 b is then performed.

The formation of the cylindrical transition bores into housing body 20 a and housing cover 20 b is performed in a joint manufacturing process with the bearing seats 108, 110.

However, the formation of the cylindrical transition bores into housing body 20 a and housing cover 20 b may also be performed in a separate manufacturing process in relation to the bearing seats 108, 110.

In the next step, the two screw bores 112, 114 for the screw rotors 16, 18 of the screw compressor 10 are formed in the housing body 20 a.

However, the formation of the screw bores 112, 114 and of the bearing seats 108 in the housing body 20 a may also be performed in a joint manufacturing process.

The formation of the two screw bores 112, 114 for the screw rotors 16, 18 of the screw compressor 10 in the housing body 20 a is performed by means of a milling process.

Provisional assembly of housing body 20 a and housing cover 20 b is then performed using the alignment tools 100, 102 in order to ensure the alignment of the screw rotor central axes with the central axes of the bearing seats 108, 110 and of the screw bores 112, 114.

During the provisional assembly of housing body 20 a and housing cover 20 b, the alignment tools 100, 102 are pushed in from the outside in each case through the bearing seats 110 for the screw rotors 16, 18 in the housing cover 20 b and through the screw bores 112, 114.

Subsequently, alignment tools 100, 102 are inserted into the two bearing seats 108, 110 in the housing body 20 a and in the housing cover 20 b.

The multiple screw connections are tightened only after the insertion of the alignment tools 100, 102 into the two bearing seats 108, 110 in the housing body 20 a and in the housing cover 20 b.

It is thus ensured that, during the pushing-in and insertion of the alignment tools 100, 102, the two bearing seats 108, 110 in the housing cover 20 b and in the housing body 20 a can be aligned relative to one another.

Then, the two bolt insertion openings 104 both in the housing body 20 a and in the housing cover 20 b are drilled, and thus produced, by means of a common drilling process.

The manufacturing direction during the joint drilling process of the two bolt insertion openings 104 runs from an outer side of the housing cover 20 b axially inwardly in the direction of the open end 120, facing toward the housing cover 20 b, of the housing body 20 a.

The joint drilling process is performed with an adjustable feed in a manufacturing direction.

At the start of the joint drilling process, the drilling tool 122 is firstly set in rotation and moved into the vicinity of the outer surface of the housing cover 20 b at the position in which the bolt insertion openings 104 are to be drilled.

The drilling tool 122 is, already at the start of the joint drilling process, aligned perpendicular to the planar inner surface 128 of the housing cover 20 b.

Then, the bolt insertion opening 104 is drilled by the drilling tool 122 as a passage bore into the housing cover 20 b in the manufacturing direction.

After the housing cover 20 b has been drilled through, this is immediately followed by the planar surface 126 of the housing body 20 a being drilled through in the manufacturing direction until the drilling tool 122 has drilled into the housing body 20 a to a predefined depth.

The bolt insertion opening 104 thus formed is therefore formed as a countersunk bore or blind bore into the housing body.

Finally, the joint drilling process is jointly ended, which involves the drilling tool 122 being fully retracted out of the housing body 20 a and the housing cover 20 b counter to the manufacturing direction.

The drilling tool 122 may be rotated during the full retraction.

In conjunction with the provisional assembly of housing body 20 a and housing cover 20 b, the housing body 20 a and the housing cover 20 b are fastened to one another by means of multiple screw connections.

After the provisional assembly of housing body 20 a and housing cover 20 b, these are separated from one another again.

The separation of housing body 20 a and housing cover 20 b is performed for at least one further machining or assembly step.

A further machining step may for example be the cutting machining in the inner regions of the housing body 20 a or of the housing cover 20 b.

Furthermore, a further machining step may constitute the cleaning and/or the deburring of the bolt insertion openings 104.

Further assembly steps may for example be the insertion of all components in the housing interior and relevant for the functional fulfilment by the screw compressor 10 and the final assembly of the housing 20.

During the assembly of housing body 20 a and housing cover 20 b, in each case one fit bolt 106 is then inserted into the bolt insertion openings 104, which fit bolt is seated both in the housing body 20 a and in the housing cover 20 b.

The fit bolt serves for correspondingly safeguarding and fixing the positioning of housing cover 20 b relative to the housing body 20 a.

The non-positively locking fastening itself may be realized for example by means of screw connections.

LIST OF REFERENCE DESIGNATIONS

-   10 Screw compressor -   12 Fastening flange -   14 Input shaft -   16 Screw rotor -   18 Screw rotor -   20 Housing -   20 a Housing body -   20 b Housing cover -   22 Oil -   24 Inlet connector -   26 Air filter -   28 Air inlet -   30 Valve insert -   32 Air feed channel -   34 Air outlet pipe -   36 Riser line -   40 Temperature sensor -   42 Holder for an air deoiling element -   42 Air deoiling element -   44 Filter screen or known filter or oil separation devices -   46 Air exit opening -   48 Check valve -   50 Minimum pressure valve -   51 Air outlet -   52 Riser line -   54 Filter and check valve -   56 Nozzle -   58 Oil return line -   59 Oil drain screw -   60 Projection -   62 Oil filter -   64 Oil filter inlet channel -   66 Thermostat valve -   68 Return line -   70 Bearing -   72 Nozzle -   74 Cooler, heat exchanger -   76 Safety valve -   78 Bypass line -   80 Relief valve -   82 Oil level sensor -   100 Alignment tool -   102 Alignment tool -   104 Bolt insertion opening -   106 Fit bolt -   108 Bearing seat -   110 Bearing seat -   112 Screw bore -   114 Screw bore -   116 First bearing insertion portion -   118 Second bearing insertion portion -   120 Open end of the housing body -   122 Manufacturing tool -   124 Partially open end of the housing body -   126 Planar surface of the housing body -   128 Planar inner surface of the housing cover -   130 Planar outer surface of the housing cover 

1-15. (canceled)
 16. A method for producing a housing of a screw compressor, wherein the housing has at least one housing body and at least one housing cover, the method comprising the steps of: forming bearing seats for at least one screw rotor of the screw compressor in the housing body and in the housing cover; forming at least one screw bore for the at least one screw rotor of the screw compressor in the housing body; provisionally assembling the housing body and the housing cover using at least one alignment tool in order to ensure alignment of a screw rotor central axis with central axes of the bearing seats and of the screw bore; and forming at least one bolt insertion opening into both the housing body and the housing cover by way of at least one joint manufacturing process.
 17. The method as claimed in claim 16, wherein the forming of the bearing seats for the at least one screw rotor of the screw compressor in the housing body and in the housing cover is performed in separate manufacturing processes.
 18. The method as claimed in claim 16, wherein in conjunction with the provisional assembly of the housing body and the housing cover, the housing body and the housing cover are fastened to one another by at least one screw connection.
 19. The method as claimed in claim 18, wherein in conjunction with the provisional assembly of the housing body and the housing cover, the alignment tool is pushed in from outside through the bearing seat for the screw rotor in the housing cover and through the screw bore and is thus inserted into the bearing seats in the housing body and in the housing cover.
 20. The method as claimed in claim 19, wherein the screw connection is tightened only after the insertion of the alignment tool into the bearing seats in the housing body and in the housing cover, such that, during the pushing-in and insertion of the alignment tool, the bearing seats in the housing cover and in the housing body are alignable relative to one another.
 21. The method as claimed in claim 16, wherein the alignment tool is of cylindrical and stepped form such that it has at least one first bearing insertion portion with a first diameter and at least one second bearing insertion portion with a second diameter.
 22. The method as claimed in claim 21, wherein after inserting the alignment tool, the first bearing insertion portion thereof is inserted in the bearing seat in the housing body and the second bearing insertion portion is inserted in the bearing seat in the housing cover.
 23. The method as claimed in claim 16, wherein after the provisional assembly, a manufacturing direction during the joint manufacturing process of the at least one bolt insertion opening runs from an outer side of the housing cover axially inwardly in the direction of the open end, facing toward the housing cover, of the housing body.
 24. The method as claimed in claim 23, wherein the joint manufacturing process of the at least one bolt insertion opening is performed by at least one cutting manufacturing process.
 25. The method as claimed in claim 24, wherein the cutting manufacturing process is drilling.
 26. The method as claimed in claim 24, wherein the cutting manufacturing process is performed by at least one cutting manufacturing tool, wherein the manufacturing tool is rotated and is of rotationally symmetrical form.
 27. The method as claimed in claim 16, wherein after the provisional assembly, the housing body and the housing cover are separated from one another for at least one further machining or assembly step.
 28. The method as claimed in claim 16, wherein during the assembly of the housing body and the housing cover, a fit bolt is inserted into the at least one bolt insertion opening, which fit bolt is seated both partially in the housing body and partially in the housing cover.
 29. The method as claimed in claim 16, wherein at least two bolt insertion openings are provided both in the housing cover and in the housing body.
 30. A housing of a screw compressor manufactured by the method according to claim
 16. 31. A screw compressor having at least one housing manufactured by the method according to claim
 16. 